1. Field of the Invention
This invention pertains to protein compositions having reduced-hygroscopic properties. More particularly, this invention pertains to reduced-hygroscopic protein compositions which comprise a homogeneous premixture of a hygroscopic protein and an effective amount of a protein complexing agent to reduce the hygroscopic properties of the protein. The improved protein compositions may be used directly or may be incorporated into edible carriers to provide a wide variety of edible compositions.
2. Description of the Background
Foods such as peanut butter, pasta, and rice serve as important sources of protein. Because these foods contain proteins which are hygroscopic, the processing and extruding of these foods are often difficult. Mixtures of these protein sources with other foods containing water tend to become thick, dry, and stiff. Extruding these foods generally requires large amounts of water to soften these materials making processing difficult and expensive. Accordingly, methods for reducing the hygroscopic properties of proteins in foods to facilitate handling are highly desirable.
A particularly rich source of protein is peanut butter which has a protein content in the range from about 23% to about 26%. The oil or fat content of peanut butter, however, is in the range from about 48% to about 53% mitigating the nutritional value of peanut butter. Attempts to make low-fat peanut butter have generally focused on removing a portion of the peanut oil found in peanuts and replacing the oil with a low-fat and low-calorie filler substitute. These low-calorie peanut butter compositions have generally been unsatisfactory because the peanut oil removal step tends to also remove a portion of the flavor components from the peanut butter resulting in a peanut butter with poor taste. In addition, the low-fat filler substitutes generally do not provide the texture and consistency properties of conventional peanut butter. Aqueous low-fat filler substitutes, in particular, tend to be absorbed by the hygroscopic peanut butter protein resulting in dry, undesirable, peanut butter compositions. Accordingly, low-fat peanut butters having reduced-hygroscopic properties but with the flavor and texture of conventional peanut butters are desirable.
U.S. Pat. No. 4,863,753, issued to Hunter et al., discloses a reduced-calorie peanut butter composition in which a portion of the peanut oil is replaced by triglycerides containing medium chain fatty acids.
U.S. Pat. No. 4,814,195, issued to Yokoyama et al., discloses a reduced-calorie peanut butter composition containing from about 15% to about 40% of a low-calorie solid bulking agent such as polydextrose or microcrystalline cellulose.
U.S. Pat. No. 4,228,190, issued to Wallgren et al., discloses a margarine composition in the form of a water-in-oil emulsion which comprises a fat phase present in an amount from about 35% to about 65% and an aqueous precipitated protein phase, present in an amount from about 35% to about 65%. Wallgren et al. forms the aqueous precipitated protein phase by coagulating milk protein with rennet and the calcium already present in casein. Wallgren et al. does not teach to add a protein complexing agent.
U.S. Pat. No. 3,580,729, issued to Darragh et al., discloses a peanut spread supplemented with from about 15% to about 25% of soybean protein and from about 15% to about 25% of liquid vegetable oil.
U.S. Pat. No. 3,552,980, issued to Cooper et al., discloses a spreadable food product consisting of two discrete spreads in contact with each other. One spread is hydrophilic such as a peanut butter and the other spread is a modified sweet aqueous spread such as a jelly. The sweet aqueous spread is modified to contain in the non-aqueous portion less than 50% carbohydrates having a molecular weight of less than about 200 to prevent migration of moisture from the sweet aqueous spread to the hydrophilic spread.
U.S. Pat. No. 2,388,991, issued to Oatman, discloses a method for precipitating casein from dried skim milk which consists of mixing the dried skim milk with fresh skim milk and precipitating the casein with an acid, sour whey, or rennet.
While the above references disclose a variety of improved food compositions, none of the above disclosures has solved the difficulty in processing hygroscopic proteins. Thus it would be commercially advantageous to provide protein compositions having reduced-hygroscopic properties to facilitate the processing of these foods. The present invention provides such improved protein compositions having reduced-hygroscopic properties without the disadvantages characteristic of previously known products. This invention also pertains to methods for preparing these reduced-hygroscopic protein compositions and the edible compositions in which they may be employed.